Technetium Resources
Nearly all technetium is produced synthetically, and only minute amounts are found in nature. Naturally occurring technetium occurs as a spontaneous fission product in uranium ore or by neutron capture in molybdenum ores. The chemical properties of this silvery gray, crystalline transition metal are intermediate between rhenium and manganese. Chemical Properties Atomic Number 43 Atomic Mass (99) g/mol Electronegativity 1.9 Density 11.5 g/cm^3 at 20 degrees C Melting Point 2200 degrees C Boiling Point 4877 degrees C General Information The existence of technetium was predicted by Dmitri Mendeleev, a Russian chemist also credited with creating the first version of the Periodic Table. The first discovery of technetium is credited to Carlo Perrier and Emilio Segré in 1937 in their laboratory at the University of Palermo in Sicily, Italy. It was first found in a sample of molybdenum that had been bombarded with deuterons in a cyclotron. Technetium was the first element that was successfully produced synthetically. Scientists once believed that it could only exist in the laboratory, but this has been found to be untrue as the spectral lines of technetium have also been detected in red giant stars. This new information has led to more research on the presence of heavy elements in the stars of the universe. Technetium is only found on Earth in small amounts in uranium ore. When it is attained, technetium is a silvery-gray solid. Naturally occurring technetium occurs as a result of spontaneous nuclear fission in uranium or by neutron capture in molybdenum ores. To make Tc with Mo, Mo-98 must be struck with neutrons for it to become Mo-99 by absorbing an electron. Then through beta-decay, it will transform into Tc-99. The longevity of technetium can be enhanced by making it through nuclear fission of U-235. Small amounts of Technetium can be extracted from nuclear fuel rods that have already been used. Technecium-99 is also a product of the detonation of nuclear weapons. Uses of Technetium A stable isotope of Technetium, Technetium-99m, is used in medical tests. Technetium-99m is a radioactive tracer that can be detected in the human body using various medical equipment. It is administered through an IV and emits radiation that attaches to chemicals found in tumors. The radioactive tracers can then be detected and give the location of a tumor.n be used to study problems with the circulatory system.Technetium-99m is used in this manner to study the brain, thyroid, lungs, liver, gallbladder, kidneys, bones, and blood. Combining Tc-99m can change its tracing properties. For example, combining Tc-99m with a tin compound helps it bind to red blood cells, which can then be used to study problems with the circulatory system. Combining Tc-99m with a pyrophosphate ion will make it bind to calcium deposits in damaged heart muscle tissue, and this can be used to determine the extent of damage done after a heart attack. Technetium-99 decomposes by beta decay which means it emits beta particles. In addition, it has a very large half-life (about 211,000 years) allowing it to decay very slowly. Because of these reasons it is a standard beta emitter and is used for equipment calibration. Technetium-95 has a half life of 61 days, and is used as a radioactive tracer. Technetium can also be used as a catalyst, and the pertechnetate ion can protect carbon steels and iron from corrosion. However, this property is limited by the radioactivity of technetium. Environmental Impacts Because technetium is produced in nuclear reactors, gaseous diffusion from these facilities contributes the most technetium into the environment. A little technetium also escapes into the environment through its use in medical diagnosis. Recent studies that have investigated the impact of technetium on soil and vegitation indicate that despite its radioactivity, technetium has a significantly lower impact than may be expected. However, plants readily take up Technetium-99 in the presence of oxygen, and it is also able to transfer from seawater to any animals living in that seawater. This suggests that we must be careful with the amount of Technetium that is entering the environment, because even though we have not found significant evidence suggesting that it is harmful to the environment, it has an extremely long half-life and will remain in the environment for a long time once it has been released. Humans can take in technetium through food or water that has been contaminated, often found in higher concentrations near contaminated facilities such as nuclear fuel plants. Once it has entered the human body, technetium-99 tends to concentrate in the thyroid gland and gastrointestinal tract. The body is able to excrete half of the ingested Tc-99 within 60 hours of ingestion, and nearly all Tc-99 will be excreted from the body within a month. This is further evidence suggesting that despite its radioactivity, technetium does not have as large of an environmental impact as one might originally think. Supply and Demand According to a study carried out by the Nuclear Energy Agency, the annual demand for technetium-99m in the global market will increase 2.1% from 2010 to 2020. Although it had been brought up that there were technetium shortages in some parts of the world, 60% of the survey subjects expect that the supply will be stable. The expected stability of supply, as the study shows, is to increase from 2021 to 2030, which indicates increase in technetium supply. Because Technetium can be synthesized from both molybdenum and uranium, it is not likely that there will be any shortages compared to demand. Sources http://en.wikipedia.org/wiki/Technetium http://upload.wikimedia.org/wikipedia/commons/8/84/Periodic_table.svg http://www.epa.gov/radiation/radionuclides/technetium.html http://www.chemicool.com/elements/technetium.html http://www.lenntech.com/periodic/elements/tc.htm http://www.oecd-nea.org/med-radio/reports/long-term-assessment-99mtc.pdf http://pubs.acs.org/doi/abs/10.1021/es00098a008 Category:Sources